First code changes to allow eventual Moore streaming

Initial streaming functionality

This MR addresses the infrastructure required to configure the future streaming from a line configuration point of view

I will build the streaming to multiple files functionality on top of the MDF functionality a separate MRs

Note the issue #268 (closed) that addresses future proper implementaion of assigning routing bit numbers to stream names

I have been able to access the routing bits in the output DST with this snippet. It all looks reasonable

Starts to address Streaming work from the DPA side, see https://gitlab.cern.ch/lhcb-dpa/project/-/issues/24.